Today’s Clean Tech Could Power the World by 2050

Using existing technologies, the world could convert almost entirely to green power by mid-century — and it wouldn’t cost much more than people now spend on energy, says a new analysis of global energy use.

The conclusions contradict the notion that green energy is still too small-scale, inefficient and expensive to support civilization.

“It’s really an optimization problem,” said study co-author Mark Jacobson, a Stanford University civil engineer. “There’s no magic, you don’t need new technologies for most of it. It’s just a different way of thinking of the system.”

In two papers in press in EnergyPolicy (.pdf), Jacobson and coauthor Mark Delucchi of the University of California, Davis outline a plan to power the planet using renewables.

They ranked the alternatives by comparing efficiency with health and environmental benefits. Wind, solar, geothermal and water power came out on top, and biofuels on bottom. Nuclear power fell in-between, as did coal burned using carbon-capturing smokestacks. These were then evaluated in terms of costs, materials and reliability.

According to a 2008 study by the federal Energy Information Administration, the world will need 17 trillion watts of power by 2030. The United States will need almost 3 trillion watts. In Jacobson and Delucci’s model, most of the needed power couldcome from electricity, as opposed to combustion, oil or natural gas.

Ninety percent of that power would come from wind and solar energy. Geothermal and hydroelectric sources would contribute about 4 percent of thepower, and 2 percent would come from wave and tidal power.

The duo considered only energy producers that have already been demonstrated to work, and can be scaled up to be part of a global energy system without major technological innovations. They estimate that the total energy cost in such a system should be similar to today’s.

“All the techniques we’re talking about are completely recyclable and sustainable theoretically, as long as the population doesn’t explode,” Jacobson said.

One lingering concern about wind and solar energy is inconsistency. Wind doesn’t always blow, and the sun goes down at night. But because wind energy tends to peak at night and solar energy is greatest during the day, linking both energy sources together could help solve that problem. Hydroelectric power could fill in the gaps. Far-flung geographic areas could be connected via a “supergrid” to make sure the lights stay on.

Other energy experts think the plan seems feasible.

“From what I saw, it’s carefully done,” said Jonathan Koomey of Lawrence Berkeley National Laboratory, who was not involved in the work. “If you take it as a back-of-the-envelope, high level, envisioning the future of what we want to create, this is a good example of that kind of work. I think it’s credibly done.”

“I think it’s generally true that one finds there are no absolutely insurmountable technical barriers,” said Ryan Wiser, an expert in renewable energy policies at Lawrence Berkeley National Laboratory, also not involved in the study. “The question isn’t fundamentally a technical one.”

Whether green energy is ready for mass adoption is no longer a matter of science, conclude Jacobson and Delucchi.

“The obstacles to realizing this transformation of the energy sector are primarily social and political.”